As a conventional example, a lighting device and lighting fixture are introduced in a Japanese Patent Application Publication JP 2015-103505 A [Document 1]. Alighting fixture described in Document 1 includes a plurality of light emitting diode (LED) groups (LED loads) different from each other in luminous colors. The lighting fixture includes a lighting device and emits mixed light as a result of the lighting device mixing light from the plurality of LED groups by turning on the plurality of LED groups in order, in time division. The lighting device includes a plurality of switching elements connected to the plurality of LED groups in series respectively. The lighting device is configured to adjust a quantity of light from each of the plurality of LED groups and adjust a chromaticity of mixed light by way of a controller controlling the plurality of switching elements.
The controller has a table in which dimming color signals inputted from an external apparatus are corresponding to sets of various control parameters. When the controller receives the dimming color signal indicating the luminous color and/or emission intensity (brightness), the controller provides repeatedly turning on light source switches in order, based on the received dimming color signal referring to the table. In this manner, each of the plurality of LED groups repeats operation of turning on the light source switches in order, and emits mixed light having color corresponding to the received dimming color signal.
Incidentally, in the lighting device and lighting fixture of Document 1, lengths of on-periods of the plurality of switching elements may be different from each other because the controller individually controls the plurality of switching elements by time division. For example, when the controller provides toning control (adjusts the chromaticity) so that the luminous color of the mixed light is similar to the luminous color of light from one LED group of the plurality of LED groups (which are different from each other in luminous color), the on-period of the switching element corresponding to the one LED group is longer than those of the switching elements corresponding to the other LED groups. Relatively, the on-periods of the switching elements corresponding to the other LED groups are shorter. In this case, flicker, such as video flicker may occur due to the other LED groups.